In view of current enhanced interest in the prevention of terrorist activity, there is a need for practical and sensitive neutron radiation detectors which can detect fissile materials and other sources of neutron radiation. Towards this end, there is a high demand for hand-held or portable devices including for example, Hand Held Radioisotope Identification Devices (HHRIID's) with additional neutron detection capability. Standards have in fact been adopted (e.g., ANSI N42.34) to meet current performance demands.
A desirable radiation detector able to detect neutron radiation should demonstrate improved functionality and identification performance; it should be able to be easily deployable, and have low total cost of ownership. Currently used neutron detectors include gas proportional counters as well as liquid scintillators. Gas proportional counters commonly utilize a gaseous composition, such as helium-3 (a He isotope) or a boron-10 (a B isotope) containing gas, e.g., 10BF3. In order to achieve a suitable neutron detection sensitivity, a large number of neutron capture nuclides is needed; due to the very low atomic density presented by the gases, a relatively large containment area and high pressures can thus be required to house the large volume occupied by the gaseous composition. The manufacturing and ownership costs of such large gas pressurized detectors can be extremely high. Further, pressurized gas containers are subject to Federal code regulations for handling and transport and severely limit the portability of gas proportional counters. Liquid scintillators are sensitive to gamma radiation and also suffer from the drawback of being relatively large in size due to their low density.
Thus, a portable, solid-based neutron radiation detector with high neutron sensitivity, low gamma sensitivity, and small volume is needed to address at least some of the concerns above.